diff --git a/README.md b/README.md
index 6101f6f..52b8699 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ Options:
   -l <location>    Lat,Lon,Hgt (static mode) e.g. 30.286502,120.032669,100
   -t <date,time>   Scenario start time YYYY/MM/DD,hh:mm:ss
   -T <date,time>   Overwrite TOC and TOE to scenario start time
-  -d <duration>    Duration [sec] (max: 300)
+  -d <duration>    Duration [sec] (dynamic mode max: 300 static mode max: 86400)
   -o <output>      I/Q sampling data file (default: gpssim.bin)
   -s <frequency>   Sampling frequency [Hz] (default: 2600000)
   -b <iq_bits>     I/Q data format [1/8/16] (default: 16)
diff --git a/gpssim.c b/gpssim.c
index 73dc1d5..9f3e68b 100644
--- a/gpssim.c
+++ b/gpssim.c
@@ -1655,13 +1655,13 @@ void usage(void)
 		"  -l <location>    Lat,Lon,Hgt (static mode) e.g. 35.681298,139.766247,10.0\n"
 		"  -t <date,time>   Scenario start time YYYY/MM/DD,hh:mm:ss\n"
 		"  -T <date,time>   Overwrite TOC and TOE to scenario start time\n"
-		"  -d <duration>    Duration [sec] (max: %.0f)\n"
+		"  -d <duration>    Duration [sec] (dynamic mode max: %.0f static mode max: %d)\n"
 		"  -o <output>      I/Q sampling data file (default: gpssim.bin)\n"
 		"  -s <frequency>   Sampling frequency [Hz] (default: 2600000)\n"
 		"  -b <iq_bits>     I/Q data format [1/8/16] (default: 16)\n"
 		"  -i               Disable ionospheric delay for spacecraft scenario\n"
 		"  -v               Show details about simulated channels\n",
-		((double)USER_MOTION_SIZE)/10.0);
+		((double)USER_MOTION_SIZE) / 10.0, STATIC_MAX_DURATION);
 
 	return;
 }
@@ -1825,12 +1825,6 @@ int main(int argc, char *argv[])
 			break;
 		case 'd':
 			duration = atof(optarg);
-			if (duration<0.0 || duration>((double)USER_MOTION_SIZE)/10.0)
-			{
-				printf("ERROR: Invalid duration.\n");
-				exit(1);
-			}
-			iduration = (int)(duration*10.0+0.5);
 			break;
 		case 'i':
 			ionoutc.enable = FALSE; // Disable ionospheric correction
@@ -1862,6 +1856,13 @@ int main(int argc, char *argv[])
 		llh[2] = 10.0;
 	}
 
+	if (duration<0.0 || duration>((double)USER_MOTION_SIZE) / 10.0 && !staticLocationMode || duration>STATIC_MAX_DURATION && staticLocationMode)
+	{
+		printf("ERROR: Invalid duration.\n");
+		exit(1);
+	}
+	iduration = (int)(duration*10.0 + 0.5);
+
 	// Buffer size	
 	samp_freq = floor(samp_freq/10.0);
 	iq_buff_size = (int)samp_freq; // samples per 0.1sec
@@ -1904,13 +1905,6 @@ int main(int argc, char *argv[])
 		llh2xyz(llh,xyz[0]); // Convert llh to xyz
 
 		numd = iduration;
-		
-		for (iumd=1; iumd<numd; iumd++)
-		{
-			xyz[iumd][0] = xyz[0][0];
-			xyz[iumd][1] = xyz[0][1];
-			xyz[iumd][2] = xyz[0][2];
-		}
 	}
 /*
 	printf("xyz = %11.1f, %11.1f, %11.1f\n", xyz[0][0], xyz[0][1], xyz[0][2]);
@@ -2141,7 +2135,10 @@ int main(int argc, char *argv[])
 				sv = chan[i].prn-1;
 
 				// Current pseudorange
-				computeRange(&rho, eph[ieph][sv], &ionoutc, grx, xyz[iumd]);
+				if (!staticLocationMode)
+					computeRange(&rho, eph[ieph][sv], &ionoutc, grx, xyz[iumd]);
+				else
+					computeRange(&rho, eph[ieph][sv], &ionoutc, grx, xyz[0]);
 				chan[i].azel[0] = rho.azel[0];
 				chan[i].azel[1] = rho.azel[1];
 
@@ -2288,7 +2285,10 @@ int main(int argc, char *argv[])
 			}
 
 			// Update channel allocation
-			allocateChannel(chan, eph[ieph], ionoutc, grx, xyz[iumd], elvmask);
+			if (!staticLocationMode)
+				allocateChannel(chan, eph[ieph], ionoutc, grx, xyz[iumd], elvmask);
+			else
+				allocateChannel(chan, eph[ieph], ionoutc, grx, xyz[0], elvmask);
 
 			// Show ditails about simulated channels
 			if (verb==TRUE)
diff --git a/gpssim.h b/gpssim.h
index ea9b5c7..5cad835 100644
--- a/gpssim.h
+++ b/gpssim.h
@@ -16,6 +16,9 @@
 /*! \brief Maximum number of user motion points */
 #define USER_MOTION_SIZE (3000) // max duration at 10Hz
 
+/*! \brief Maximum duration for static mode*/
+#define STATIC_MAX_DURATION (86400) // second
+
 /*! \brief Number of subframes */
 #define N_SBF (5) // 5 subframes per frame